kindly explain me in description abt improvement exam for tybcom ... as i have secured only 43% in ty 2010-11 ?

Is it mandatory to score 60% if u r giving improvement exam ? If m giving tybcom this year again of all the sub .. will it be (60/40 marks) or full 100 marks paper i have to give ? And what i have to study the old course or the new course with respect to subject (eco,mhrm,tax) ? kindly help with me